Implicitly import `java` flag for `kotlin` and `scala` flags

[ikhoon]

kotlin and scala flags are added for configuring the default settings for Kotlin and Scala.
However, they can not activate the common features enabled by java such as publishing, relocation, coverage, and so on.
Even though the kotlin flag is set to a pure Kotlin project, it also needs a java flag.
Otherwise, the project will not be configured or executed as expected.

I think we can assume kotlin and scala is a superset of java flag. So it is convenient to implicitly import java flag for them.

- // Before
- includeWithFlags ':my-kotlin-project', 'java', 'publish', 'relocate', 'kotlin'
+ // After
+ includeWithFlags ':my-kotlin-project', 'kotlin', publish', 'relocate'